`SetCommonContentType` is no longer respected when `SetBody()` is called

[gg718]

Summary

I am not sure exactly when this was broken, but it works as expected in v3.37.2 and does not work in v3.40.1, so at some point between then, calling SetBody on the request seems to disregard the Content-Type set at the global level.

Repro

package main

import (
    "github.com/imroc/req/v3"
)

func main() {
    client := req.C().
        DevMode().
        SetCommonContentType("application/json")

    _, _ = client.R().SetBody("").Post("https://example.com")
}

Expected

...
content-type: application/json; charset=utf-8
...

Actual

...
content-type: text/plain; charset=utf-8
...

[imroc]

Nice catch! It's been fixed in the latest release.

[gg718]

Thanks for the speedy fix!